1. Department of Orthopaedic Surgery, College of Medicine, Kyung Hee University Spine Centre, Kyung Hee University Hospital at Gangdong, Seoul, Korea
2. Department of Orthopaedic Surgery, College of Medicine, Hallym University, Kangdong Sacred Heart Hospital, Seoul, Korea
3. Department of Orthopedic Surgery, Eutteum Orthopedic Hospital, Gyeonggi-do, Korea
4. Department of Orthopaedic Surgery, The Affiliated Shunde Hospital of Guangzhou Medical University, Foshan City, China